const app = getApp();

Page({
  data: {
    start: '2013-02-21',
    day: null
  },

  onLoad: function() {
    const diff = new Date() - new Date(this.data.start);
    const diffDay = Math.floor( diff / ( 3600 * 24 * 1000));
    
    this.setData({
      day: diffDay
    });
  }
});
